To power such a motor, a power chain successively includes a converter, an insulating contactor, cables connected between the insulating contactor and the input terminals of the motor.
If an electric fault is detected of the short-circuit type, the insulating contactor is opened to insulate the converter from the electric motor. As a result, the components of the converter are protected against the electrical power generated by the electric motor operating at that time as a current source, since it is driven by the wheels of the moving railway vehicle.
However, opening the insulating contactor does not make it possible to insulate an electric fault downstream from the insulating contactor, i.e., an internal fault of the electric motor or an external fault of the electric motor, for example between the connecting cables.
Yet such a fault downstream from the insulating converter is generally associated with the formation of an electric arc, which can lead to the outbreak of a fire or the destruction of the electric motor. In the latter case, there is a risk of the rotor being blocked inside the stator of the motor, leading to a feared event requiring immobilization of the train and evacuation of the passengers.
To guarantee the operating protection of such a permanent magnet synchronous electric motor, it is necessary to manage any possible failure to avoid any feared event.
Document EP 2,634,884 thus provides for equipping the power chain with additional controlled switches making it possible to dead short-circuit phases of the motor, to avoid the formation and spread of an electric arc. However, such a device does not make it possible to resolve all types of faults internal to the machine.